The combined mid-sized producer, with operations in Canada and Mexico, will have 2015 output of 375,000 to 425,000 ounces of gold.

Although analysts said the deal makes sense for the two miners - Alamos has excess cash and AuRico has a mine in Ontario that is ramping up production - competing offers could emerge.

"We believe AuRico, particularly Young-Davidson (Ontario mine), offers a compelling asset at current valuation levels for an interloper and as such, we see room for a potential premium deal to occur," Raymond James analyst Phil Russo said in a note to clients.

A Yamana spokesman declined to comment, and Goldcorp and Agnico did not immediately respond to requests for a statement.

A stumbling block to a competing bid may be a $83.3 million side deal Alamos struck to buy a 9.9 percent stake in AuRico via a private placement for C$2.99 a share, a 21 percent discount to AuRico's closing price on Friday.

This deal is not contingent on the acquisition closing, so any rival bidder for AuRico would have to pay a premium to buy out those shares, on top of standard break fees.

AuRico shares rose 7 percent to C$4.04, while those in Alamos were up 6 percent at C$7.86 in afternoon trading.

ALAMOS GOLD INC

Alamos and AuRico shareholders will each own about half the combined company, which is called Alamos Gold.

A new company, AuRico Metals Inc, will be formed to hold interests in certain AuRico assets, including the Kemess project in British Columbia.

AuRico Chairman Alan Edwards will be chairman of the combined company, while Alamos Chief Executive John McCluskey will be CEO. Five directors each from AuRico and Alamos will sit on the board.

Maxit Capital LP was Alamos' financial adviser, while Torys LLP was its legal counsel in Canada and the United States.

AuRico was advised by Scotiabank. Its Canadian legal counsel was Fasken Martineau and its U.S. legal counsel was Paul Weiss. (Editing by Don Sebastian. Editing by Andre Grenon)